1. Field of the Invention
The present invention relates to a lifting and drying device that cleans a substrate by immersing a disk-like substrate with a central hole into a cleaning liquid disposed in a cleaning tank and lifts and dries the substrate, and a method of manufacturing a magnetic recording medium substrate or a magnetic recording medium using the same.
Priority is claimed on Japanese Patent Application No. 2010-183211, filed on Aug. 18, 2010, the content of which is incorporated herein by reference.
2. Description of Related Art
For example, a disk-like magnetic recording medium substrate with a central hole has been used as a hard disk drive mounted on an information device or the like. Such a magnetic recording medium substrate is manufactured by performing various treatments such as cutting, grinding, polishing, sputtering, and plating on a substrate formed of an aluminum alloy, glass or the like. After such treatments, cleaning and drying of the surface of the substrate is performed.
However, in recent years, the recording density of magnetic recording media has been further increased due to the demand for a large storage capacity of a recording medium and a compact size of an information device or the like. In such a magnetic recording medium substrate or magnetic recording medium using the same, high flatness is demanded which is capable of achieving a reduction of a floating height of a magnetic head running on the recording surface thereof in a floating state.
For this reason, in the magnetic recording medium substrate and the magnetic recording medium, a high-level cleaning method capable of removing dust or the like adhering to the surface of the substrate after performing various surface treatments such as polishing and sputtering thereon, and a drying method for cleanly drying the cleaned substrate are demanded.
Conventionally, as a method of cleaning and drying the substrate, in the case of a substrate with a large diameter, a method has been performed in which a plurality of substrates is received inside a container which is called as a carrier, is scrubbed and cleaned by a plurality of cleaning brushes while being conveyed inside a liquid, and is rotated to be spun and dried.
Furthermore, a cleaning device is proposed which sets a magnetic disk substrate or the like as a workpiece and cleans the substrate using a liquid of a plurality of cleaning tanks by conveying the substrate through a conveyor in order to remove foreign matter adhering to the surface of the workpiece after performing a surface treatment such as polishing on the surface thereof (refer to Japanese Unexamined Patent Application, First Publication No. 2001-96245).
Furthermore, a wafer drying device is proposed which sets a semiconductor substrate as a wafer, accommodates a cassette accommodating a plurality of wafers inside a cradle, and rotates the cradle while holding the wafers so as to be parallel to each other using a member with V-shaped grooves in order to prevent water droplets or dust from remaining on the wafer (refer to Japanese Unexamined Patent Application, First Publication No. 8-45894).
Furthermore, there is proposed a spinning and drying device that removes a cleaning liquid adhering to a disk with a central hole by rotating the disk, wherein a part of a contact portion where a chuck member chucking the outer peripheral portion of a disk and the disk to be chucked contact each other is set as a non-contact portion where the chuck member and the disk do not contact each other, so that a cleaning liquid retained at the chuck member is efficiently removed (refer to Japanese Unexamined Patent Application, First Publication No. 2003-257017).
Furthermore, there is provided a spinning and drying device that removes a cleaning liquid adhering to a disk with a central hole by rotating the disk, wherein the disk is chucked in an upright state by a chuck member chucking the inner peripheral portion of the disk, and an air supply unit is provided to supply air backward in the rotation direction of the contact portion between the chuck member and the disk, so that the cleaning liquid retained at the chuck member is efficiently removed (refer to Japanese Patent No. 2782838).
Furthermore, as a method of drying a wafer-like substrate, a lifting and drying method is known (refer to Japanese Unexamined Patent Application, First Publication No. 10-189529). The lifting and drying method is a method of immersing a cleaned wafer into pure water while holding it by a chucking device, raising the chucking device so as to raise the upper portion of the wafer from the pure water and remove the pure water from the exposed portion, and lifting the entire surface of the wafer from the pure water so as to dry the wafer.
Since the above-described lifting and drying method has a device with a simple structure and may process a plurality of substrates at the same time, the method has been widely used as a method of drying a wafer-like substrate. However, the lifting and drying method is not readily used to dry the magnetic recording medium substrate or the magnetic recording medium. That is, when the lifting and drying method is used, for example, as schematically shown in FIGS. 3A to 3C, pure water W rising due to the surface tension splashes back at the time when a substrate D moves away from the pure water W, and bursting liquid droplets P adhere to the substrate D again. Furthermore, in many cases, contaminants are condensed at the liquid droplets P adhering to the substrate D again, so that the contaminants form a drying stain on the substrate D. Then, since the drying stain is formed on the recording surface of the magnetic recording medium, the position of the drying stain becomes a bad sector of the magnetic recording medium.